Collagen biofabric and methods of preparation and use therefor

Abstract

The present invention relates to collagenous membranes produced from amnion, herein referred to as a collagen biofabric. The collagen biofabric of the invention has the structural integrity of the native non-treated amniotic membrane, i.e., the native tertiary and quaternary structure. The present invention provides a method for preparing a collagen biofabric from a placental membrane, preferably a human placental membrane having a chorionic and amniotic membrane, by decellularizing the amniotic membrane. In a preferred embodiment, the amniotic membrane is completely decellularized. The collagen biofabric of the invention has numerous utilities in the medical and surgical field including for example, blood vessel repair, construction and replacement of a blood vessel, tendon and ligament replacement, wound-dressing, surgical grafts, ophthalmic uses, sutures, and others. The benefits of the biofabric are, in part, due to its physical properties such as biomechanical strength, flexibility, suturability, and low immunogenicity, particularly when derived from human placenta.

Description

[0001] This application is a continuation in part of U.S. application Ser. No. 10 / 106,653 filed on Mar. 26, 2002, which is incorporated herein by reference in its entirety.1. FIELD OF THE INVENTION[0002] The present invention relates to collagenous membranes produced from amnion, herein referred to as a collagen biofabric. The collagen biofabric of the invention has the structural integrity of the native non-treated amniotic membrane, i.e., the native tertiary and quaternary structure. The present invention provides a method for preparing a collagen biofabric from a placental membrane, preferably a human placental membrane having a chorionic and amniotic membrane, by decellularizing the amniotic membrane. In a preferred embodiment, the amniotic membrane is completely decellularized. The collagen biofabric of the invention has numerous utilities in the medical and surgical field including for example, blood vessel repair, construction and replacement of a blood vessel, tendon and lig...

AI Technical Summary

Benefits of technology

[0013] The present invention relates, in part, to the discovery by the inventors of a novel method of preparation of a collagen biofabric from placenta, preferably a human placenta, that results in a novel collagen biofabric with improved physical and biophysical properties. Preferably the method of preparation involves minimal manipulation of the amniotic membrane. The collagen biofabric of the invention unlike those described in the prior art, due to the way by which it is processed, has an intact native tertiary and quaternary structure The present invention also provides a placental-derived amniotic membrane or biofabric having superior characteristics of increased tensile strength, suturability, and reduced immunogenicity resulting in reduced host-graft rejection. The present invention also provides a placental-derived amniotic membrane or biofabric that can be stored as dehydrated sheets without freezing or cryopreservation. Preferably, the placental-derived amniotic membrane is derived from a human placenta for use in human patients. However, the same methods can be employed using placentas from various animal species for veterinary use in animal patients.

[0014] The present invention provides a method of preparing a collagen biofabric comprising providing a placenta, preferably a human placenta, separating the amnionic and chorionic layers from each other, and decellularizing the amniotic membrane while preserving the architecture of the underlying extracellular matrix. The method further entails washing and drying the decellularized membrane. This method yields a dehydrated, decellularized biofabric that can remain stable under sterile storage conditions at room temperature and that is subsequently rehydrated and grafted to or implanted into a subject.

Problems solved by technology

Possible potential problems with xenogenic tissues (tissues from other species) carrying zoonotic diseases or causing cross-species rejection have made these tissues less desirable.

The scarcity of human donor tissues for grafting is a growing problem that has stimulated the development of new materials for tissue grafting.

Most often these sources of biological raw material are scarce, difficult to obtain, and very costly.

These studies were mainly in animals and human trials proved disappointing.

The process of freezing the tissue at any time during its preparation makes the Tseng amniotic membrane brittle, and even more brittle after the steps of thawing and activation.

In addition, the thawing and activation steps add time required for the handling of the amniotic membrane.

Furthermore, because of the brittleness of the Tseng amniotic membrane caused by the freezing step in the preservation and preparation process, a structural support or backing is required to ensure structural integrity of the Tseng amniotic membrane during storage.

This presents the added difficulty of separating the preserved amniotic membrane from the backing, which, due to its brittleness can be difficult to handle and separate intact.

Separation of the amnion membrane from the backing thus increases the likelihood of rupture of the membrane, and increases the length of time required to activate the amniotic membrane to allow for thorough impregnation of the activation solution into the frozen amniotic membrane prior to performing the surgical procedure, leading to increased preparation time in the surgical suite.

Storage and shipping are also complicated by the requirement of -80.degree. C. freezing.

Finally, the membranes of Tseng are not generally decellularized; as a result, the amniotic membranes so prepared are typically opaque and do not have a uniform structural composition.

One method for cross-linking described in the '312 Patent employs high heat treatment, preferably at 100.degree. to 110.degree. C., which is believed to adversely affect the native conformation of collagen.

This material, however, is treated during preparation with proteases as part of a decellularization step, which likely results in destruction and / or disruption of native conformation of the components of the matrix; thus, the resulting collagen matrix does not maintain its native conformation.

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